Accurate Drop of a GPS Beacon Using the X8 Fixed-Wing UAV

• Main Author: Grindheim, Vegard
• Other Authors: Fossen, Thor Inge
• Format: Master Thesis
• Language: English
• Published: NTNU 2015
• Subjects: Kybernetikk og robotikk (2 årig); Arctic; Sea ice
• Online Access: http://hdl.handle.net/11250/2352442

Improved possibilities for transport, as a consequence of diminishing ice mass in the Arctic, leads to more activity in these areas. Some of the greatest dangers of heightened presence in the Arctic is associated with sea ice. To decrease the dangers of sea ice in Arctic areas, fixed-wing UAVs can be used to find and tag dangerous ice with GPS based position transmitting beacons. This would allow traffic and offshore installations to operate more safely by knowing about dangers beforehand. This thesis will focus on the specific task of making a UAV system capable of hitting sea ice with a GPS beacon by an unguided air drop. This task has several parts, including calculating the aerial release point and guiding the UAV to this point with high accuracy. The combined drop accuracy and precision required from this system is to be able to hit sea ice with a radius of 10 meters 95% of the time. 10 m is approximately the radius of a small floe. Several approach methods were applied with different controllers and path planners to accurately guide the UAV to the aerial release point. The best combination of these used optimization techniques combined with a line-of-sight path-following controller. This combination acquired a theoretical accuracy of 1.63 m and a precision of 7.14 m from simulated results. This was combined to give a 95% chance of hitting within 8.77 m of the sea ice centre, which is better than the required accuracy set in this thesis. This result was unfortunately not confirmed by flight tests, as unforeseen circumstances prevented flight time when the system was completed. However, early flight tests validates the correctness of the simulation results to some degree.